# SyncSharedMemory::read

(PECL sync >= 1.1.0)

SyncSharedMemory::read — Copy data from named shared memory

### Beschreibung

public SyncSharedMemory::read(int `$start` = 0, int `$length` = ?)

Copies data from named shared memory.

### Parameter-Liste

`start`
  The start/offset, in bytes, to begin reading.

  > Hinweis: If the value is negative, the starting position will begin at the specified number of bytes from the end of the shared memory segment.

`length`
  The number of bytes to read.

  > Hinweis: If unspecified, reading will stop at the end of the shared memory segment. If the value is negative, reading will stop the specified number of bytes from the end of the shared memory segment.

### Rückgabewerte

A string containing the data read from shared memory.

### Beispiele

Beispiel #1 SyncSharedMemory::__construct() example

`<?php
// You will probably need to protect shared memory with other synchronization objects.
// Shared memory goes away when the last reference to it disappears.
$mem = new SyncSharedMemory("AppReportName", 1024);
if ($mem->first())
{
// Do first time initialization work here.
}
$result = $mem->write("report.txt");
$result = $mem->read(3, -4);
var_dump($result);
?>`

Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:

    string(3) "ort"

### Siehe auch

- SyncSharedMemory::__construct() - Constructs a new SyncSharedMemory object
- SyncSharedMemory::first() - Check to see if the object is the first instance system-wide of named shared memory
- SyncSharedMemory::write() - Copy data to named shared memory
- SyncSharedMemory::read()

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